This invention relates to systems and methods for respiratory function analysis and control, and in particular to systems and methods for dynamically analyzing and controlling the respiration of a patient.
Controlling a patient""s respiration is useful for many applications, including pulmonary function testing and evaluation, CT and MRI imaging of the chest, respiratory muscle training, and weaning patients off ventilators. Most currently available systems for controlling and evaluating respiratory function are relatively inflexible, and do not have the capability to precisely and dynamically control respiratory function. Moreover, some available methods of controlling respiratory function can be uncomfortable for the patient, particularly methods requiring the patient to hold his or her breath for extended periods of time.
The present invention provides systems and methods for dynamically and accurately controlling a patient""s respiratory function. The methods allow substantial flexibility in the evaluation process. The methods further allow limiting patient discomfort during respiratory function control procedures.
A dynamic respiratory control device includes a fast-response valve capable of dynamically imposing multiple resistive loads on the flow of respiratory gas to and from a patient. The resistive loads are applied according to measured flow rates, patient lung volumes, and/or mouthpiece pressures. The device can precisely constrain tidal breathing, provide precise volumetric control of the airway, and impose multiple specific inspiratory and/or expiratory loading functions to evaluate respiratory function. The device is useful for pulmonary is function testing, CT and MRI imaging of the chest, combined CT imaging/interventional radiology, radiotherapy delivery to the thorax/abdomen, and/or as a resistive muscle trainer for weaning patients off ventilators and for respiratory muscle training.
The present invention provides a dynamic respiratory control apparatus comprising: a respiratory function valve for dynamically controlling a respiratory gas flow for a patient; a flow rate monitoring device positioned in a flow path of the respiratory gas, in fluidic communication with the valve, for measuring a flow rate of the respiratory gas; and a control unit electrically connected to the monitoring device and the valve, for receiving flow rate data from the monitoring device and for dynamically controlling the valve to apply an intermediate resistive load to the flow according to the flow rate data. Further provided is a dynamic respiratory control method comprising: generating flow rate data characterizing a flow of a respiratory gas between a respiratory function valve and a patient; and dynamically controlling the valve to apply an intermediate resistive load to the flow according to the flow rate data. The real-time feedback and flexibility in applying multiple inspiratory and/or expiratory resistive loads allow improved respiratory function evaluation and control, as well as improved respiratory muscle training.
The present invention further provides a control unit electrically connected to the monitoring device and the valve, for receiving flow rate data from the monitoring device, determining a lung volume of the patient from the flow rate data, and dynamically controlling the valve to maintain the lung volume between a first predetermined value and a second predetermined value. Further provided is a dynamic respiratory control method comprising: generating flow rate data characterizing a flow of a respiratory gas between a respiratory function valve and a patient; determining a lung volume of the patient from the flow rate data; and dynamically controlling the valve to maintain the lung volume between a first predetermined value and a second predetermined value. Actively maintaining the patient""s lung volume between two predetermined values allows limiting the range of motion of the patient""s organs during imaging or therapy procedures, without requiring the patient to hold his or her breath.